Conventionally, mobile Internet Protocol (IP) communications utilize a home agent and foreign agent, such as a packet data serving node, to provide mobile service to mobile devices. The home agent is a router on the mobile device's home network that delivers information from or to the mobile device. The foreign agent is a router or server located on a network visited by the mobile node when away from home. The foreign agent provides mobile services for the mobile device while the mobile device is visiting the network associated with the foreign agent. The foreign agent generates a path to the home agent and provides the mobile device with mobile service.
A home network that utilizes a single home agent creates a single point of failure. When the home agent is taken offline, the mobile service to the mobile device is interrupted until a new home agent is connected to the home network. Some networks are configured with multiple home agents to eliminate the single point of failure. For instance, a network may utilize one-to-one redundancy mechanisms that provide a backup home agent for each active home agent. The backup and active home agent share the same configuration and are synchronized periodically. Accordingly, when the active home agent fails, the backup home agent is added to the network.
Although the one-to-one redundancy mechanism provides fault-tolerance by eliminating the single point of failure, the synchronization process may prevent the backup home agent from quickly replacing the active home agent and may delay service to the mobile device. Also, the mechanism is limited to IP version four (IPv4) and may not effectively work with IP version six (IPv6) communication networks.